Development Pipeline

Janux’s initial development programs are designed to activate T cells within the tumor microenvironment. The company leverages its proprietary tumor activated T cell engager (TRACTr) and its tumor activated immunomodulator (TRACIr) platforms to develop bispecific molecules that once activated are precision engineered to bind to specific tumor antigens and to T cells, thereby focusing T cells to attack the cancer while limiting toxicity elsewhere in the body. Activation of the TRACTrs and TRACIrs within the tumor microenvironment limits toxicity elsewhere in the body.

JANX007, a PSMA-targeted TRACTr immunotherapy, has demonstrated encouraging safety and efficacy in Phase 1 for metastatic castration-resistant prostate cancer (mCRPC) in heavily pre-treated patients with a median of four prior lines of therapy. In December 2024, Janux reported positive interim clinical data from the Phase 1a dose escalation portion of the trial in 16 mCRPC patients.

In 16 patients, JANX007 displayed: 100% achieved best PSA50 declines, with 63% achieving best PSA90 and 31% achieving best PSA99 declines. These responses were durable, with 75% and 50% of patients maintaining PSA50 and 90 declines, respectively, for at least 12 weeks. Deep and durable PSA responses were observed irrespective of resistance driver aberration status, or prior treatments with a taxane or ARPi. In RECIST-evaluable patients, anti-tumor activity was observed with confirmed and unconfirmed partial responses in 50% (4/8) of patients.

Updated results as of April 2025 showed a median radiographic progression-free survival (rPFS) of 7.5 months across the same group of 16 patients, and 7.9 months in those treated at higher doses. Six-month rPFS rates were 65% overall and 78% in the higher-dose group. JANX007 has displayed a well-tolerated safety profile, with most adverse events being mild (Grade 1–2) and primarily occurring in Cycle 1.